Some thermal printers can perform an option operation, such as a tear-off operation and a peeling operation. In the option operation, printed labels are sometimes conveyed to a predetermined position (referred to as an option position) and then stopped after printing has been performed on the designated number of labels. For example, in the tear-off operation, a liner is automatically advanced until a portion of the liner between a printed label and the next unprinted label arrives at the position of a cutter, and then the liner is stopped. In the peeling operation, a liner is automatically advanced until a printed label arrives at a position where it is peeled off, and then the liner is stopped.
A thermal printer performs printing while conveying a label in a state where the label is sandwiched between a thermal head and a platen roller. At this time, a predetermined pressure is applied between the thermal head and the platen roller. Therefore, if the label is left for a long period of time in a state where it is sandwiched between the thermal head and the platen roller, the label may deform, e.g., become dent, depending on its material. This has a possibility of negatively affecting the printing quality, e.g., blurring print on a portion that has deformed.
Patent Literature 1 discloses a technique to prevent deformation of a thermal sheet sandwiched between a thermal head and a platen roller. In a thermal printer of Patent Literature 1, if a state in which no printing is performed lasts for a predetermined time period or longer, a leading end of the thermal sheet retracts to a position which is upstream relative to a print standby position and in which no stress is applied.